Filters are commonly used in cameras to provide an interface between the subject being imaged and the electronic imaging system of the camera. For example, color filters may be used in photography to compensate for differences between the dynamic range of the light sensors within the camera and the range of available light relative to the subject being photographed.
In some cameras, red (R), green (G), and blue (B) filters are used. Often, standard electronic photography cameras use a color filter array or matrix wherein the RGB filter elements are disposed adjacent to the electronic light sensors of the camera in a particular arrangement or pattern to obtain a better conversion of the light from the subject being imaged into light usable by the camera. For example, in order to obtain a more realistic image of subjects in ordinary sun-lit conditions, many cameras having RGB filters utilize more green filter matrix elements than red or blue. Essentially, in these systems, the green filter elements of the RGB color filter array are over represented.
Evidence of some diseases manifest in skin discolorations which can be found by trained professionals through examination of the facial skin. For example, a certain redness of the facial skin can be an early indication of an oxygen deficient condition or of other blood diseases or the like. A yellowness of the skin can be an early sign of liver dysfunction or of a jaundice condition. However, standard photography cameras are not trained for redness or yellowness imaging and, further, are not well suited for imaging the human skin in general.
Although it is desirable to obtain a live diagnosis from trained professionals during an office visit, some medical conditions present themselves through dues in the characteristics of the facial skin over time. Accordingly, a single office visit might not lead to any meaningful diagnosis. However, meaningful quantification of redness, yellowness, or other discolorations of the skin of a patient over the course of multiple office visits remains an unresolved challenge using existing electronic photographic equipment.